Fluid pump

ABSTRACT

A pair of fluid pressure operated diaphragm pumps, the diaphragms of which are disposed in separate housings and connected together for common reciprocatory movements. A valve body provides support for the housings and for a connection between the diaphragms. The valve body contains a reversing valve, a pilot valve, and a pressure relief valve in a pump operating fluid circuit which includes primary pressure chambers in the housings at one side of the diaphragms. The housings define secondary chambers at the other side of the diaphragms for pumping fluids isolated from the pump operating fluids.

United States Patent 1191 Wanner [451 Feb. 12,1974

1 1 FLUID PUMP [76] Inventor: William F. Wanner, 5805 View Ln.,

Minneapolis, Minn. 55436 [22] Filed: June 16, 1972 [21] Appl. No.:263,692

[52] U.S. Cl 417/393, 91/313, 91/329,

137/99, 137/625.69, 417/395 [51] Int. Cl. F04b 17/00, F0413 35/00 [58]Field of Search... 417/395, 393, 401, 344, 345;

91/304, 313 X, 329 X, 445, 446; 137/99, 624.14, 625.69 X

[56] References Cited UNITED STATES PATENTS 2,679,209 5/1954 Fischer etal. 417/395 X 3,064,582 11/1962 Knights 417/393 X 2,866,415 12/1958Montelius 417/345 514,608 2/1894 Weatherhead... 417/395 X 3,106,939/1963 Flick 137/625.69

2,239,715 4/1941 Hollander et al. 91/313 X Primary ExaminerCarlton R.Croyle Assistant Examiner-Richard Sher Attorney, Agent, or FirmMerchant,Gould, Smith & Edell [57] ABSTRACT A pair of fluid pressure operateddiaphragm pumps, the diaphragms of which are disposed in separatehousings and connected together for common reciprocatory movements. Avalve body provides support for the housings and for a connectionbetween the diaphragms. The valve body contains a reversing valve, a

pilot valve, and a pressure relief valve in a pump operating fluidcircuit which includes primary pressure chambers in the housings at oneside of the diaphragms. The housings define secondary chambers at theother side of the diaphragms for pumping fluids isolated from the pumpoperating fluids.

3 Claims, 6 Drawing Figures PATE-NIEDFEBI 2 3. 79 1 .768

SHEET 3 0F 3 64 22 26 75 min 62 78 in 71 A 5 FLUID PUMP Diaphragm pumpsin and of themselves are well known, as are fluid pressure operateddiaphragm pumps, the latter being often used as pulse dampening devices.Heretofore, in arrangements wherein a pair of diaphragm pumps are tiedtogether for common reciprocation of the diaphragms, mechanical linkageconnecting the diaphragms has required the use of spring loaded snapaction mechansim to initiate reversal of reciprocatory movement, toavoid stalling of the pumps. Also, such systems have required the use offour-way valves mechanically linked to the mechanical connectionsbetween a pair of diaphragms.

SUMMARY OF THE INVENTION An important object of this invention is theprovision of an improved fluid pressure operated diaphragm pump whichincludes means for preventing stalling of the reciprocating action ofthe diaphragms.

Another object of this invention is a provision of a fluid pressurepowered diaphragm pump in a compact self-contained unit including anintegral pressure control.

Another object of this invention is a provision of a fluid pressurepowered diaphragm pump in which the differential pressure across thediaphragm is always small regardless of the operating pressure of thesystem.

To the above ends, I provide a main body which defines primary inlet andoutlet ports, a pilot valve chamber, a reversing valve chamber, andfluid pressure passages interconnecting the ports and valve members. Apair of pump housings are attached to opposite sides of the main bodyand have diaphragms therein which cooperate with the housings to defineprimary and secondary pressure chambers, the main body having fluidpassages connecting the reversing valve chamber with the primarypressure chambers. The diaphragms are disposed on a common axis and areconnected for common reciprocatory movement in their respective housingsby a rigid connector element. A reversing valve is axially movable inthe reversing valve chamber, and a pilot or shuttle valve is axiallymovable in the pilot valve chamber, the pilot valve being in the natureof a spool having an axis parallel to the axis of the diaphragms andopposite end portions each projecting to a different one of the primarychambers for abutting engagement with the diaphragm. A tubular member isaxially slideable on a diametrically reduced portion of the spool withinthe pilot valve chamber, and a pair of stop elements limit axialmovement of the tubular member relative to the spool. The spool is of alength relative to the distance between the diaphragms to provide apredetermined lost motion relationship between the spool and diaphragms.An adjustable pressure relief valve is disposed in the main body toprovide a by-pass in the primary fluid pressure circuit. The secondarypressure chambers communicate with a manifold through check valves, themanifold having secondary fluid inlet and outlet ports.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in plan of a pump producedin accordance with this invention;

FIG. 2 is a view in side elevation;

FIG. 3 is a transverse section taken on the line 3-3 of FIG. 1;

FIG. 4 is an enlarged fragmentary section taken on the line 4-4 of FIG.2;

FIG. 5 is an enlarged fragmentary section taken on the line 5-5 of FIG.1; and

FIG. 6 is a fragmentary section taken on the line 6-6 of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A generally rectangularmain body 1 is mounted on a base 2 and has bolted or otherwise rigidlysecured to its top surface a top closure plate 3. The opposite ends ofthe main body 1 are covered by end members 4 and 5 secured to the mainbody 1 by machine screws or the like 6, the end member 4 having thereinscrew threaded inlet and outlet ports 7 and 8 respectively, see FIG. 5.The ports 7 and 8 are hereinafter designated as primary ports. The mainbody 1 is bored to provide inlet and outlet passages 9 and 10respectively extending longitudinally therethrough, and registering atone end with the inlet and outlet ports 7 and 8 respectively. The endmember 5 defines a valve passage 11 having an angularly displaced inletend 12 in register with the inlet passage 9, the opposite end of thevalve passage 11 having an angularly displaced outlet end 13 in registerwith the outlet passage 10. Adjacent the inlet end 12, the valve passage11 is formed to provide a valve seat 14 for seating engagement withadjustable pressure relief valve elementlS. A coil compression spring 16is interposed between the valve element 15 and a spring seat member 17that is engaged by an adjustment screw 18 screw threaded in a mountingcap 19 mounted on the upper end of the end member 5 and secured theretoby machine screws or the like 20. A conventional pipe plug 21 is screwthreaded into the mounting cap 19 to protect the threaded opening forthe adjustment screw 18 from foreign matter.

A pair of diaphragm pumps comprise pump housings 22 and 23 andrespective diaphragms 24 and 25. Each of the housings 22 and 23 includeslaterally inner and outer generally circular housing sections 26 and 27rigidly secured together about their marginal edges by circumferentiallyspaced nut equipped screws 28, the marginal edges of the diaphragms 24and 25 being clamped between said marginal edges by the screws 28, seeparticularly FIG. 3. Other machine screws 29 extend through suitable"openings in the inner housing sections 26 and are screw threaded intoopposite sides of the main body 1 to anchor the pump housings 22 and 23to the main body 1 in axial alignment.

The diaphragms 24 and 25 may be made from any suitable sheet material,but are preferably made from flexible or plastic sheet material, such asrubber or other material that is inert to various liquids or fluids withwhich the pump may be used. The diaphragms 24 and 25 are each reinforcedat their central portions by pairs of metallic plates 30 held in face toface relationship with opposite sides of their respective diaphragms 24and 25 by machine screws 31. The diaphragms 24 and 25 are connected forcommon reciprocatory movement in their respective housings 22 and 23 bya rigid tie rod 32 extending axially of the diaphragms 24 and 25 andthrough an opening 33 extending through the body I, see FIGS. 3 and 5.As shown in FIG. 3, the opposite ends of the tie rod 32 are formed withdiametrically reduced screw threaded portions 34 that extend throughaligned central openings in the diaphragms 24 and and their respectiveplates 30, the opposite ends of the tie rods being anchored to theirrespective diaphragms 24 and 25 by anchoring nuts 35 screw threaded onthe threaded portions 34. The diaphragms 24 and 25 cooperate with theirrespective pump housing sections 26 to define primary pressure chambers36 and 37 respectively, and with their respective housing sections 27 todefine secondary pressure chambers 38 and 39 respectively.

The housing sections 27 of the pump housings 22 and 23 are provided withaxial openings 40 that communicate with the interiors of the respectivecheck valve boxes 41 and 42 each of which contain an inlet check valve43 and an outlet check valve 44, one of each being shown in FIG. 4. Apair of generally U-shaped inlet and outlet manifolds 45 and 46respectively are provided at their opposite ends with mounting flanges47 through which extend mounting screws 48 for securing the manifolds 45and 46 to opposite sides of the check valve boxes 41 and 42. Withreference to FIG. 4, it will be seen that the mounting flanges 47 arearranged to hold the check valves 43 and 44 within recesses formed inthe check valve boxes 41 and 42. Intermediate their ends, the manifolds45 and 46 are provided with respective inlet and outlet ports 49 and 50respectively, hereinafter designated as secondary inlet and outletports. It will be noted that the secondary ports communicate with thesecondary pressure chambers 38 and 39 through the manifolds 45 and 46,valve boxes 41 and 42 and housing openings 40.

Just above the inlet passage 9, the main body 1 is formed to provide acylindrical reversing valve chamber 51 disposed on an axis in spacedparallel relation to the axes of the passages 9 and 10. A reversingvalve 52 is in the nature of a spool having end lands 53 and 54, acentral land 55 and diametrically reduced portions 56 and 57 between thecentral land 55 and end lands 53 and 54 respectively. The lands 53 55are cylindrical for axial sliding movement in the chamber 51, the lands53 and 54 preferably being provided with sealing rings 58, see FIG. 5.

Above the reversing valve chamber 51 and below the tie rod opening 33,the main body 1 is bored or otherwise formed to provide the transverseopening therethrough which opening forms a pilot valve chamber 59. Apilot valve, in the nature of an elongated spool 60 includes a pair ofdiametrically enlarged end portions or lands 61 and 62, and adiametrically reduced intermediate portion or stem 63 connecting the endportions 61 and 62. With reference to FIGS. 3 and 6, it will be notedthat the lands 61 and 62 extend through suitable openings in the housingsections 26 of the diaphragm pump housings 22 and 23, the extreme endsof the valve spool 60 be adapted to abuttingly engage adjacent ones ofthe plates 30 of the diaphragms 24 and 25 respectively. The lands 61 and62 are provided adjacent their outerends'with stop collars or the like64 which limit movement of the valve spool 60 in opposite directionsrelative to the main body 1. The pilot valve 60 includes a tubularmember 65 that encompasses the shank portion 63 and is axially slideablethereon betweenva pair of axially spaced stop pins 66 projectingradially outwardly from the shank portion 63, all for a purpose whichwill hereinafter become apparent. The

pilot valve spool 60 is adapted to be moved axially with respect to thepilot valve chamber 59 by engagement of the opposite ends of the valvespool 60 with the plates 30 of the diaphragms 24 and 25. It will benoted,

particularly with reference to FIG. 3, that the axial length of thepilot valve spool 60 is substantially less than the distance between thediaphragms 24 and 25, so that there is a fair amount of lost motiontherebetween during reciprocation of the diaphragms 24 and 25 and thetie rod 32'.

Generally centrally between the opposite ends of the main body 1, afluid passage 67 extends upwardly from the inlet passage 9 through thecentral portion of the reversing valve chamber 51, and terminates in areduced passage portion 68 that communicates with the longitudinallycentral portion of the pilot valve chamber 59, see FIGS. 3, 5 and 6. Apair of laterally spaced passages 69 and 70 extend longitudinally of themain body 1 in opposite directions from the pilot valve chamber 59, andat their outer ends, register with respective ones of a pair of passages71 and 72 formed in the adjacent surfaces of the end members 5 and 4respectively. As shown particularly in FIG. 5, the passages 71 and 72communicate with adjacent ends of the reversing valve chamber 51. A pairof fluid passages 73 and 74 extend transversely of themain body 1 fromthe reversing valve chamber 51 and through the diaphragm pump housingsections 26 to the secondary pressure chambers 36 and 37 respectively.As shown in FIGS. 5 and 6, the fluid passages 73 and 74 are spaced apartin a direction axially of the reversing valve chamber 51 at oppositesides of the fluid passage 67. Another pair of fluid passages 75 and 76extend upwardly from the reversing valve chamber 51 through the outletpassage 10, the passages 75 and 76 being disposed in outwardly spacedrelation to respective passages 73 and 74, in a direction axially of thereversing valve chamber 51. The passages 75 and 76 communicate withaxially spaced portions of the pilot valve chamber 59 through connectingpassages 77 and 78 respectively, these passages. extendinglongitudinally of the main body 1 in laterally outwardly spaced relationto adjacent ones of the fluid passages 69 and 70. p

In the embodiment of the invention illustrated, it may be assumed thatthe main body 1 is of cast or moulded material, the passages 67 and 7376 being formed therein by conventional cores. The lower end of thepassage 67 is closed by the base 2, the upper ends of the cored fluidpassages 75 and 76 being closed by the closure plate 3. In theembodiment illustrated, the connecting passages 77' and 78 are drilledin the main body 1, the outer ends thereof being closed by the endmembers 4 and 5.

Operation Assuming that the secondary inlet port 49 is connected byconduit means, not shown, to a source of fluid, and that the secondaryoutlet port 50 is similarly connected to a point of delivery, pumpingfluid under pressure is introduced to the inlet passage 9 through theprimary inlet port 7. The pumping fluid flows upwardly through thepassage 67 into the reversing valve chamber 51. With the reversing valvespool 52 disposed in its position illustrated in FIG. 5, fluid will flowbetween the lands 53 and 55 outwardly through the fluid passage 73 tothe pressure chamber 36 to move the diaphragm 24 in a direction to theleft with respect to FIG. 3. As the diaphragm 24 moves inthis'direction,

the tie rod 32 carries the diaphragm 25 in the same direction. Duringthis time, the fluid passage portion 68, pilot valve chamber 59,passages 69 and 71, and the end portion of the reversing valve chamber51 adjacent the land 53, are under fluid pressure to hold the reversingvalve spool 52 in its position shown in FIG. 5. As the diaphragms 24 and25 move to the left with respect to FIG. 3 fluid is pulled into thesecondary chamber 39 from the secondary inlet 49, the fluid in thesecondary pressure chamber 38 being forced outwardly under pressurethrough the manifold 46 and secondary outlet 50. At the same time,pumping fluid in the primary pressure chamber 73 flows outwardlytherefrom through the passage 74 into the reversing valve chamber 51between the lands 54 and 55, from whence fluid flows outwardly throughthe passage 76 to the outlet passage and outlet port 8. It should herebe noted that the passages 75 and 76 intersect the passages 77 and 78respectively.

As the pump diaphragms 24 and 25 continue their movement toward the leftwith respect to FIG. 3, the inner plate 30 of the diaphragm 25abuttingly engages the end of the adjacent pilot valve land 61 to movethe pilot valve spool 60 toward the left with respect to FIG. 3. One ofthe stop pins 66 imparts movement to the tubular member 65 in commonwith the pilot valve spool 60 until the tubular member 65 moves over thepassage portion 68 sufficiently to expose the upper end of the passageportion 68 to the space between the tubular member 65 and the land 61.As soon as the passage portion 68 is thus exposed, fluid under pressuremoves into the space to impart movement to the tubular mem ber 65 to theleft with respect to FIG. 3 independently of the valve spool 60 untilthe tubular member 65 engages the opposite stop pin 66. At this time,the passage portion 68 becomes fully in register with the space betweenthe tubular member 65 and land 61 before the pilot valve spool 60 andthe diaphragms 24 and 25 have reached their limit of movement toward theleft with respect to FIG. 3. With the passage portion 68 thus uncovered,fluid under pressure flows through the fluid passages 70 and 72 to theend of the reversing valve chamber 51 adjacent the reversing valve land54 to move the reversing valve spool 52 to the left with respect to FIG.5. During this movement, fluid in the left hand end of the chamber 51flows outwardly therefrom through the passages 71 and 69, to the pilotvalve chamber 59 between the tubular member 65 and land 62 of the valvespool 60, and from thence through the passages 78 and 76 to the outletpassage 10 and primary outlet port 8. Movement of the reversing valvespool 52 to the opposite end of the valve chamber 51 exposes the passage74 to fluid pressure from the passage67, and exposes the passage 73 tothe passage 75, so that fluid may be exhausted from the primary pressurechamber 36 the primary outlet port 8 while fluid under pressure is beingintroduced to the primary pres sure chamber 37. As soon as the land 55of the reversing valve spool 52 is moved beyond the passage 67, thepumping fluid reverses the direction of movement of the diaphragms 24and 25. With reference to FIG. 3, it will be noted that the fluidpassage 67 is of greater width than the diameter of the reversing valvechamber 51, so that fluid under pressure is supplied to the passageportion 68 at all times. Thus, movement of the reversing valve spoolland 55 across the passage 67 does not shut off the supply of fluidunder pressure to the passage portion 68 and pilot valve chamber 59, sothere is no chance for the reversing valve spool 52 to stall during itsreversing movement. The shuttling movement of the tubular member 65 onthe pilot valve spool 60, together with the lost motion arrangementbetween the pilot valve spool 60 and diaphragms 24 and 25 provides forefficient and non stalling operation of the pilot valve.

The adjustable pressure relief valve element 15 opens to provide aby-pass for pumping fluid from the inlet passage 9 to the outlet passage10 when pressure in the primary pressure chambers exceeds a givenmaximum, which maximum is determined by adjustment of the screw 18.Pressure in the primary chambers 36 and 37 is determined by theloadpressure of material being pumped outwardly through the secondaryoutlet 50 by the diaphragms 24 and 25. Thus, fluid is pumped by thediaphragms 24 and 25 only on demand as indicated by a drop in pressurein the outlet manifold 46.

Most of the parts of the above described pump may be made from anysuitable metal or plastic material, and the pump may be built in anydesired size to meet various requirements. While I have shown anddescribed a commercial embodiment of my improved diaphragm pump, it willbe understood that the same is capable of modification without departurefrom the spirit and scope of the invention, as defined in the claims.

What is claimed is;

1. A fluid pump comprising:

a. a main body;

b. a pair of housings each disposed at an opposite side of said body;

c. a pair of pumping diaphragms one in each of said housings anddividing the interior of each housing into primary and secondarypressure chambers;

d. inlet and discharge manifolds disposed to communicate with saidsecondary pressure chambers and having one-way check valves therein andsecondary inlet and outlet ports respectively;

e. means connecting said diaphragms together for common reciprocatorymovement in their respective housings;

f. said main body defining primary inlet and outlet ports and passagemeans connecting said primary inlet and outlet ports to said primarychambers, said passage means including pilot and reversing valvechambers, said primary inlet port being adapted for connection to asource of fluid under pressure;

g. and a pilot valve and a reversing valve movably mounted in respectiveones of said pilot and reversing valve chambers;

h. said pilot valve being movable alternately in opposite directionsresponsive to movement of said diaphragms to control flow of fluid tosaid reversing valve chamber; said pilot valve comprising a spoolaxially movable in said pilot valve chamber and having a diametricallyreduced portion within said pilot valve chamber, a tubular memberencompassing said reduced portion and axially movable relative to saidmain body and spool, and stop means in said pilot valve chamber limitingmovements of said tubular member axially of said spool;

i. said reversing valve being fluid pressure operated and operativeresponsive to movement of said pilot valve in opposite directions todirect flow of fluid from said primary inlet and alternately to saidpriin said primary pressure chambers.

3. The fluid pump definedin claim 1, in which said stop means comprisesa pair of axially spaced stop elements projecting radially outwardly ofsaid diametrically reduced spool portion and each engageable with adifferent end of said tubular member.

I! l III It l

1. A fluid pump comprising: a. a main body; b. a pair of housings eachdisposed at an opposite side of said body; c. a pair of pumpingdiaphragms one in each of said housings and dividing the interior ofeach housing into primary and secondary pressure chambers; d. inlet anddischarge manifolds disposed to communicate with said secondary pressurechambers and havIng one-way check valves therein and secondary inlet andoutlet ports respectively; e. means connecting said diaphragms togetherfor common reciprocatory movement in their respective housings; f. saidmain body defining primary inlet and outlet ports and passage meansconnecting said primary inlet and outlet ports to said primary chambers,said passage means including pilot and reversing valve chambers, saidprimary inlet port being adapted for connection to a source of fluidunder pressure; g. and a pilot valve and a reversing valve movablymounted in respective ones of said pilot and reversing valve chambers;h. said pilot valve being movable alternately in opposite directionsresponsive to movement of said diaphragms to control flow of fluid tosaid reversing valve chamber; said pilot valve comprising a spoolaxially movable in said pilot valve chamber and having a diametricallyreduced portion within said pilot valve chamber, a tubular memberencompassing said reduced portion and axially movable relative to saidmain body and spool, and stop means in said pilot valve chamber limitingmovements of said tubular member axially of said spool; i. saidreversing valve being fluid pressure operated and operative responsiveto movement of said pilot valve in opposite directions to direct flow offluid from said primary inlet and alternately to said primary pressurechambers and from alternating primary pressure chambers to said outletport.
 2. The fluid pump defined in claim 1 in which said passage meansincludes a valve passage intermediate said primary inlet and outletports, characterized by an adjustable pressure relief valve in saidvalve passage operative to by-pass flow of fluid around said pilot andreversing valves responsive to predetermined pressure in said primarypressure chambers.
 3. The fluid pump defined in claim 1, in which saidstop means comprises a pair of axially spaced stop elements projectingradially outwardly of said diametrically reduced spool portion and eachengageable with a different end of said tubular member.